Re: big ext3 sequential write improvement in 2.5.51-mm1 gone in 2.5.53-mm1?

From: Andrew Morton (akpm@digeo.com)
Date: Thu Jan 23 2003 - 21:10:42 EST


rwhron@earthlink.net wrote:
>
> Did you add a secret sauce to 2.5.59-mm2?

I have not been paying any attention to the I/O scheduler changes for a
couple of months, so I can't say exactly what caused this. Possibly Nick's
batch expiry logic which causes the scheduler to alternate between reading
and writing with fairly coarse granularity.

> 10x sequential write improvement on ext3 for multiple tiobench threads.

OK...

I _have_ been paying attention to the IO scheduler for the past few days.
-mm5 will have the first draft of the anticipatory IO scheduler. This of
course is yielding tremendous improvements in bandwidth when there are
competing reads and writes.

I expect it will take another week or two to get the I/O scheduler changes
really settled down. Your assistance in thoroughly benching that would be
appreciated.

> 2.4.20aa1 8.24 7.21% 28.587 449134.11 0.10395 0.07086 114
> 2.5.59 9.50 5.50% 36.703 4310.62 0.00000 0.00000 173
> 2.5.59-mm2 35.28 17.69% 10.173 18950.56 0.01010 0.00000 199

boggle.

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